## Data Structure MCQ - Queue

This section focuses on the "Queue" of the Data Structure. These Multiple Choice Questions (mcq) should be practiced to improve the Data Structure skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

1. Which one of the following is an application of Queue Data Structure?

A. When a resource is shared among multiple consumers.
B. When data is transferred asynchronously (data not necessarily received at same rate as sent) between two processes
D. All of the above

2. In linked list implementation of queue, if only front pointer is maintained, which of the following operation take worst case linear time?

A. Insertion
B. Deletion
C. To empty a queue
D. Both Insertion and To empty a queue

3. Let the following circular queue can accommodate maximum six elements with the following data.What will happen after ADD O operation takes place?

```
front = 2 rear = 4
queue = _______; L, M, N, ___, ___```

A. front = 2 rear = 5
queue = ______; L, M, N, O, ___
B. front = 3 rear = 5
queue = L, M, N, O, ___
C. front = 3 rear = 4
queue = ______; L, M, N, O, ___
D. front = 2 rear = 4
queue = L, M, N, O, ___

4.How many stacks are needed to implement a queue. Consider the situation where no other data structure like arrays, linked list is available to you.

A. 1
B. 2
C. 3
D. 4

5.In a Queue, if a user tries to remove an element from empty Queue it is called _________.

A. Underflow
B. Empty collection
C. Overflow
D. Garbage Collection

6. If the elements "A", "B", "C" and "D" are placed in a queue and are deleted one at a time, in what order will they be removed?

A. ABCD
B. DCBA
C. DCAB
D. ABCD

7.A priority queue can efficiently implemented using which of the following data structures? Assume that the number of insert and peek (operation to see the current highest priority item) and extraction (remove the highest priority item) operations are almost same

A. Array
C. Heap Data Structures like Binary Heap, Fibonacci Heap
D. None of the above

8. In case of insertion into a linked queue, a node borrowed from the __________ list is inserted in the queue.

A. AVAIL
B. FRONT
C. REAR
D. None of the mentioned

9.If the MAX_SIZE is the size of the array used in the implementation of circular queue. How is rear manipulated while inserting an element in the queue?

A. rear=(rear%1)+MAX_SIZE
B. rear=rear%(MAX_SIZE+1)
C. rear=(rear+1)%MAX_SIZE
D. rear=rear+(1%MAX_SIZE)

10.Suppose a circular queue of capacity (n – 1) elements is implemented with an array of n elements. Assume that the insertion and deletion operation are carried out using REAR and FRONT as array index variables, respectively. Initially, REAR = FRONT = 0. The conditions to detect queue full and queue empty are

A. Full: (REAR+1) mod n == FRONT, empty: REAR == FRONT
B. Full: (REAR+1) mod n == FRONT, empty: (FRONT+1) mod n == REAR
C. Full: REAR == FRONT, empty: (REAR+1) mod n == FRONT
D. Full: (FRONT+1) mod n == REAR, empty: REAR == FRONT